/*
 * Copyright(c) 2013-2015 Intel Corporation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 */
#include <linux/libnvdimm.h>
#include <linux/badblocks.h>
#include <linux/export.h>
#include <linux/module.h>
#include <linux/blkdev.h>
#include <linux/device.h>
#include <linux/ctype.h>
#include <linux/ndctl.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/io.h>
#include "nd-core.h"
#include "nd.h"

LIST_HEAD(nvdimm_bus_list);
DEFINE_MUTEX(nvdimm_bus_list_mutex);

void nvdimm_bus_lock(struct device *dev)
{
	struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);

	if (!nvdimm_bus)
		return;
	mutex_lock(&nvdimm_bus->reconfig_mutex);
}
EXPORT_SYMBOL(nvdimm_bus_lock);

void nvdimm_bus_unlock(struct device *dev)
{
	struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);

	if (!nvdimm_bus)
		return;
	mutex_unlock(&nvdimm_bus->reconfig_mutex);
}
EXPORT_SYMBOL(nvdimm_bus_unlock);

bool is_nvdimm_bus_locked(struct device *dev)
{
	struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);

	if (!nvdimm_bus)
		return false;
	return mutex_is_locked(&nvdimm_bus->reconfig_mutex);
}
EXPORT_SYMBOL(is_nvdimm_bus_locked);

struct nvdimm_map {
	struct nvdimm_bus *nvdimm_bus;
	struct list_head list;
	resource_size_t offset;
	unsigned long flags;
	size_t size;
	union {
		void *mem;
		void __iomem *iomem;
	};
	struct kref kref;
};

static struct nvdimm_map *find_nvdimm_map(struct device *dev,
		resource_size_t offset)
{
	struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);
	struct nvdimm_map *nvdimm_map;

	list_for_each_entry(nvdimm_map, &nvdimm_bus->mapping_list, list)
		if (nvdimm_map->offset == offset)
			return nvdimm_map;
	return NULL;
}

static struct nvdimm_map *alloc_nvdimm_map(struct device *dev,
		resource_size_t offset, size_t size, unsigned long flags)
{
	struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);
	struct nvdimm_map *nvdimm_map;

	nvdimm_map = kzalloc(sizeof(*nvdimm_map), GFP_KERNEL);
	if (!nvdimm_map)
		return NULL;

	INIT_LIST_HEAD(&nvdimm_map->list);
	nvdimm_map->nvdimm_bus = nvdimm_bus;
	nvdimm_map->offset = offset;
	nvdimm_map->flags = flags;
	nvdimm_map->size = size;
	kref_init(&nvdimm_map->kref);

	if (!request_mem_region(offset, size, dev_name(&nvdimm_bus->dev))) {
		dev_err(&nvdimm_bus->dev, "failed to request %pa + %zd for %s\n",
				&offset, size, dev_name(dev));
		goto err_request_region;
	}

	if (flags)
		nvdimm_map->mem = memremap(offset, size, flags);
	else
		nvdimm_map->iomem = ioremap(offset, size);

	if (!nvdimm_map->mem)
		goto err_map;

	dev_WARN_ONCE(dev, !is_nvdimm_bus_locked(dev), "%s: bus unlocked!",
			__func__);
	list_add(&nvdimm_map->list, &nvdimm_bus->mapping_list);

	return nvdimm_map;

 err_map:
	release_mem_region(offset, size);
 err_request_region:
	kfree(nvdimm_map);
	return NULL;
}

static void nvdimm_map_release(struct kref *kref)
{
	struct nvdimm_bus *nvdimm_bus;
	struct nvdimm_map *nvdimm_map;

	nvdimm_map = container_of(kref, struct nvdimm_map, kref);
	nvdimm_bus = nvdimm_map->nvdimm_bus;

	dev_dbg(&nvdimm_bus->dev, "%s: %pa\n", __func__, &nvdimm_map->offset);
	list_del(&nvdimm_map->list);
	if (nvdimm_map->flags)
		memunmap(nvdimm_map->mem);
	else
		iounmap(nvdimm_map->iomem);
	release_mem_region(nvdimm_map->offset, nvdimm_map->size);
	kfree(nvdimm_map);
}

static void nvdimm_map_put(void *data)
{
	struct nvdimm_map *nvdimm_map = data;
	struct nvdimm_bus *nvdimm_bus = nvdimm_map->nvdimm_bus;

	nvdimm_bus_lock(&nvdimm_bus->dev);
	kref_put(&nvdimm_map->kref, nvdimm_map_release);
	nvdimm_bus_unlock(&nvdimm_bus->dev);
}

/**
 * devm_nvdimm_memremap - map a resource that is shared across regions
 * @dev: device that will own a reference to the shared mapping
 * @offset: physical base address of the mapping
 * @size: mapping size
 * @flags: memremap flags, or, if zero, perform an ioremap instead
 */
void *devm_nvdimm_memremap(struct device *dev, resource_size_t offset,
		size_t size, unsigned long flags)
{
	struct nvdimm_map *nvdimm_map;

	nvdimm_bus_lock(dev);
	nvdimm_map = find_nvdimm_map(dev, offset);
	if (!nvdimm_map)
		nvdimm_map = alloc_nvdimm_map(dev, offset, size, flags);
	else
		kref_get(&nvdimm_map->kref);
	nvdimm_bus_unlock(dev);

	if (!nvdimm_map)
		return NULL;

	if (devm_add_action_or_reset(dev, nvdimm_map_put, nvdimm_map))
		return NULL;

	return nvdimm_map->mem;
}
EXPORT_SYMBOL_GPL(devm_nvdimm_memremap);

u64 nd_fletcher64(void *addr, size_t len, bool le)
{
	u32 *buf = addr;
	u32 lo32 = 0;
	u64 hi32 = 0;
	int i;

	for (i = 0; i < len / sizeof(u32); i++) {
		lo32 += le ? le32_to_cpu((__le32) buf[i]) : buf[i];
		hi32 += lo32;
	}

	return hi32 << 32 | lo32;
}
EXPORT_SYMBOL_GPL(nd_fletcher64);

struct nvdimm_bus_descriptor *to_nd_desc(struct nvdimm_bus *nvdimm_bus)
{
	/* struct nvdimm_bus definition is private to libnvdimm */
	return nvdimm_bus->nd_desc;
}
EXPORT_SYMBOL_GPL(to_nd_desc);

struct device *to_nvdimm_bus_dev(struct nvdimm_bus *nvdimm_bus)
{
	/* struct nvdimm_bus definition is private to libnvdimm */
	return &nvdimm_bus->dev;
}
EXPORT_SYMBOL_GPL(to_nvdimm_bus_dev);

static bool is_uuid_sep(char sep)
{
	if (sep == '\n' || sep == '-' || sep == ':' || sep == '\0')
		return true;
	return false;
}

static int nd_uuid_parse(struct device *dev, u8 *uuid_out, const char *buf,
		size_t len)
{
	const char *str = buf;
	u8 uuid[16];
	int i;

	for (i = 0; i < 16; i++) {
		if (!isxdigit(str[0]) || !isxdigit(str[1])) {
			dev_dbg(dev, "%s: pos: %d buf[%zd]: %c buf[%zd]: %c\n",
					__func__, i, str - buf, str[0],
					str + 1 - buf, str[1]);
			return -EINVAL;
		}

		uuid[i] = (hex_to_bin(str[0]) << 4) | hex_to_bin(str[1]);
		str += 2;
		if (is_uuid_sep(*str))
			str++;
	}

	memcpy(uuid_out, uuid, sizeof(uuid));
	return 0;
}

/**
 * nd_uuid_store: common implementation for writing 'uuid' sysfs attributes
 * @dev: container device for the uuid property
 * @uuid_out: uuid buffer to replace
 * @buf: raw sysfs buffer to parse
 *
 * Enforce that uuids can only be changed while the device is disabled
 * (driver detached)
 * LOCKING: expects device_lock() is held on entry
 */
int nd_uuid_store(struct device *dev, u8 **uuid_out, const char *buf,
		size_t len)
{
	u8 uuid[16];
	int rc;

	if (dev->driver)
		return -EBUSY;

	rc = nd_uuid_parse(dev, uuid, buf, len);
	if (rc)
		return rc;

	kfree(*uuid_out);
	*uuid_out = kmemdup(uuid, sizeof(uuid), GFP_KERNEL);
	if (!(*uuid_out))
		return -ENOMEM;

	return 0;
}

ssize_t nd_sector_size_show(unsigned long current_lbasize,
		const unsigned long *supported, char *buf)
{
	ssize_t len = 0;
	int i;

	for (i = 0; supported[i]; i++)
		if (current_lbasize == supported[i])
			len += sprintf(buf + len, "[%ld] ", supported[i]);
		else
			len += sprintf(buf + len, "%ld ", supported[i]);
	len += sprintf(buf + len, "\n");
	return len;
}

ssize_t nd_sector_size_store(struct device *dev, const char *buf,
		unsigned long *current_lbasize, const unsigned long *supported)
{
	unsigned long lbasize;
	int rc, i;

	if (dev->driver)
		return -EBUSY;

	rc = kstrtoul(buf, 0, &lbasize);
	if (rc)
		return rc;

	for (i = 0; supported[i]; i++)
		if (lbasize == supported[i])
			break;

	if (supported[i]) {
		*current_lbasize = lbasize;
		return 0;
	} else {
		return -EINVAL;
	}
}

static ssize_t commands_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	int cmd, len = 0;
	struct nvdimm_bus *nvdimm_bus = to_nvdimm_bus(dev);
	struct nvdimm_bus_descriptor *nd_desc = nvdimm_bus->nd_desc;

	for_each_set_bit(cmd, &nd_desc->cmd_mask, BITS_PER_LONG)
		len += sprintf(buf + len, "%s ", nvdimm_bus_cmd_name(cmd));
	len += sprintf(buf + len, "\n");
	return len;
}
static DEVICE_ATTR_RO(commands);

static const char *nvdimm_bus_provider(struct nvdimm_bus *nvdimm_bus)
{
	struct nvdimm_bus_descriptor *nd_desc = nvdimm_bus->nd_desc;
	struct device *parent = nvdimm_bus->dev.parent;

	if (nd_desc->provider_name)
		return nd_desc->provider_name;
	else if (parent)
		return dev_name(parent);
	else
		return "unknown";
}

static ssize_t provider_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct nvdimm_bus *nvdimm_bus = to_nvdimm_bus(dev);

	return sprintf(buf, "%s\n", nvdimm_bus_provider(nvdimm_bus));
}
static DEVICE_ATTR_RO(provider);

static int flush_namespaces(struct device *dev, void *data)
{
	device_lock(dev);
	device_unlock(dev);
	return 0;
}

static int flush_regions_dimms(struct device *dev, void *data)
{
	device_lock(dev);
	device_unlock(dev);
	device_for_each_child(dev, NULL, flush_namespaces);
	return 0;
}

static ssize_t wait_probe_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct nvdimm_bus *nvdimm_bus = to_nvdimm_bus(dev);
	struct nvdimm_bus_descriptor *nd_desc = nvdimm_bus->nd_desc;
	int rc;

	if (nd_desc->flush_probe) {
		rc = nd_desc->flush_probe(nd_desc);
		if (rc)
			return rc;
	}
	nd_synchronize();
	device_for_each_child(dev, NULL, flush_regions_dimms);
	return sprintf(buf, "1\n");
}
static DEVICE_ATTR_RO(wait_probe);

static struct attribute *nvdimm_bus_attributes[] = {
	&dev_attr_commands.attr,
	&dev_attr_wait_probe.attr,
	&dev_attr_provider.attr,
	NULL,
};

struct attribute_group nvdimm_bus_attribute_group = {
	.attrs = nvdimm_bus_attributes,
};
EXPORT_SYMBOL_GPL(nvdimm_bus_attribute_group);

static void set_badblock(struct badblocks *bb, sector_t s, int num)
{
	dev_dbg(bb->dev, "Found a poison range (0x%llx, 0x%llx)\n",
			(u64) s * 512, (u64) num * 512);
	/* this isn't an error as the hardware will still throw an exception */
	if (badblocks_set(bb, s, num, 1))
		dev_info_once(bb->dev, "%s: failed for sector %llx\n",
				__func__, (u64) s);
}

/**
 * __add_badblock_range() - Convert a physical address range to bad sectors
 * @bb:		badblocks instance to populate
 * @ns_offset:	namespace offset where the error range begins (in bytes)
 * @len:	number of bytes of poison to be added
 *
 * This assumes that the range provided with (ns_offset, len) is within
 * the bounds of physical addresses for this namespace, i.e. lies in the
 * interval [ns_start, ns_start + ns_size)
 */
static void __add_badblock_range(struct badblocks *bb, u64 ns_offset, u64 len)
{
	const unsigned int sector_size = 512;
	sector_t start_sector;
	u64 num_sectors;
	u32 rem;

	start_sector = div_u64(ns_offset, sector_size);
	num_sectors = div_u64_rem(len, sector_size, &rem);
	if (rem)
		num_sectors++;

	if (unlikely(num_sectors > (u64)INT_MAX)) {
		u64 remaining = num_sectors;
		sector_t s = start_sector;

		while (remaining) {
			int done = min_t(u64, remaining, INT_MAX);

			set_badblock(bb, s, done);
			remaining -= done;
			s += done;
		}
	} else
		set_badblock(bb, start_sector, num_sectors);
}

static void badblocks_populate(struct list_head *poison_list,
		struct badblocks *bb, const struct resource *res)
{
	struct nd_poison *pl;

	if (list_empty(poison_list))
		return;

	list_for_each_entry(pl, poison_list, list) {
		u64 pl_end = pl->start + pl->length - 1;

		/* Discard intervals with no intersection */
		if (pl_end < res->start)
			continue;
		if (pl->start >  res->end)
			continue;
		/* Deal with any overlap after start of the namespace */
		if (pl->start >= res->start) {
			u64 start = pl->start;
			u64 len;

			if (pl_end <= res->end)
				len = pl->length;
			else
				len = res->start + resource_size(res)
					- pl->start;
			__add_badblock_range(bb, start - res->start, len);
			continue;
		}
		/* Deal with overlap for poison starting before the namespace */
		if (pl->start < res->start) {
			u64 len;

			if (pl_end < res->end)
				len = pl->start + pl->length - res->start;
			else
				len = resource_size(res);
			__add_badblock_range(bb, 0, len);
		}
	}
}

/**
 * nvdimm_badblocks_populate() - Convert a list of poison ranges to badblocks
 * @region: parent region of the range to interrogate
 * @bb: badblocks instance to populate
 * @res: resource range to consider
 *
 * The poison list generated during bus initialization may contain
 * multiple, possibly overlapping physical address ranges.  Compare each
 * of these ranges to the resource range currently being initialized,
 * and add badblocks entries for all matching sub-ranges
 */
void nvdimm_badblocks_populate(struct nd_region *nd_region,
		struct badblocks *bb, const struct resource *res)
{
	struct nvdimm_bus *nvdimm_bus;
	struct list_head *poison_list;

	if (!is_nd_pmem(&nd_region->dev)) {
		dev_WARN_ONCE(&nd_region->dev, 1,
				"%s only valid for pmem regions\n", __func__);
		return;
	}
	nvdimm_bus = walk_to_nvdimm_bus(&nd_region->dev);
	poison_list = &nvdimm_bus->poison_list;

	nvdimm_bus_lock(&nvdimm_bus->dev);
	badblocks_populate(poison_list, bb, res);
	nvdimm_bus_unlock(&nvdimm_bus->dev);
}
EXPORT_SYMBOL_GPL(nvdimm_badblocks_populate);

static void append_poison_entry(struct nvdimm_bus *nvdimm_bus,
		struct nd_poison *pl, u64 addr, u64 length)
{
	lockdep_assert_held(&nvdimm_bus->poison_lock);
	pl->start = addr;
	pl->length = length;
	list_add_tail(&pl->list, &nvdimm_bus->poison_list);
}

static int add_poison(struct nvdimm_bus *nvdimm_bus, u64 addr, u64 length,
			gfp_t flags)
{
	struct nd_poison *pl;

	pl = kzalloc(sizeof(*pl), flags);
	if (!pl)
		return -ENOMEM;

	append_poison_entry(nvdimm_bus, pl, addr, length);
	return 0;
}

static int bus_add_poison(struct nvdimm_bus *nvdimm_bus, u64 addr, u64 length)
{
	struct nd_poison *pl, *pl_new;

	spin_unlock(&nvdimm_bus->poison_lock);
	pl_new = kzalloc(sizeof(*pl_new), GFP_KERNEL);
	spin_lock(&nvdimm_bus->poison_lock);

	if (list_empty(&nvdimm_bus->poison_list)) {
		if (!pl_new)
			return -ENOMEM;
		append_poison_entry(nvdimm_bus, pl_new, addr, length);
		return 0;
	}

	/*
	 * There is a chance this is a duplicate, check for those first.
	 * This will be the common case as ARS_STATUS returns all known
	 * errors in the SPA space, and we can't query it per region
	 */
	list_for_each_entry(pl, &nvdimm_bus->poison_list, list)
		if (pl->start == addr) {
			/* If length has changed, update this list entry */
			if (pl->length != length)
				pl->length = length;
			kfree(pl_new);
			return 0;
		}

	/*
	 * If not a duplicate or a simple length update, add the entry as is,
	 * as any overlapping ranges will get resolved when the list is consumed
	 * and converted to badblocks
	 */
	if (!pl_new)
		return -ENOMEM;
	append_poison_entry(nvdimm_bus, pl_new, addr, length);

	return 0;
}

int nvdimm_bus_add_poison(struct nvdimm_bus *nvdimm_bus, u64 addr, u64 length)
{
	int rc;

	spin_lock(&nvdimm_bus->poison_lock);
	rc = bus_add_poison(nvdimm_bus, addr, length);
	spin_unlock(&nvdimm_bus->poison_lock);

	return rc;
}
EXPORT_SYMBOL_GPL(nvdimm_bus_add_poison);

void nvdimm_forget_poison(struct nvdimm_bus *nvdimm_bus, phys_addr_t start,
		unsigned int len)
{
	struct list_head *poison_list = &nvdimm_bus->poison_list;
	u64 clr_end = start + len - 1;
	struct nd_poison *pl, *next;

	spin_lock(&nvdimm_bus->poison_lock);
	WARN_ON_ONCE(list_empty(poison_list));

	/*
	 * [start, clr_end] is the poison interval being cleared.
	 * [pl->start, pl_end] is the poison_list entry we're comparing
	 * the above interval against. The poison list entry may need
	 * to be modified (update either start or length), deleted, or
	 * split into two based on the overlap characteristics
	 */

	list_for_each_entry_safe(pl, next, poison_list, list) {
		u64 pl_end = pl->start + pl->length - 1;

		/* Skip intervals with no intersection */
		if (pl_end < start)
			continue;
		if (pl->start >  clr_end)
			continue;
		/* Delete completely overlapped poison entries */
		if ((pl->start >= start) && (pl_end <= clr_end)) {
			list_del(&pl->list);
			kfree(pl);
			continue;
		}
		/* Adjust start point of partially cleared entries */
		if ((start <= pl->start) && (clr_end > pl->start)) {
			pl->length -= clr_end - pl->start + 1;
			pl->start = clr_end + 1;
			continue;
		}
		/* Adjust pl->length for partial clearing at the tail end */
		if ((pl->start < start) && (pl_end <= clr_end)) {
			/* pl->start remains the same */
			pl->length = start - pl->start;
			continue;
		}
		/*
		 * If clearing in the middle of an entry, we split it into
		 * two by modifying the current entry to represent one half of
		 * the split, and adding a new entry for the second half.
		 */
		if ((pl->start < start) && (pl_end > clr_end)) {
			u64 new_start = clr_end + 1;
			u64 new_len = pl_end - new_start + 1;

			/* Add new entry covering the right half */
			add_poison(nvdimm_bus, new_start, new_len, GFP_NOWAIT);
			/* Adjust this entry to cover the left half */
			pl->length = start - pl->start;
			continue;
		}
	}
	spin_unlock(&nvdimm_bus->poison_lock);
}
EXPORT_SYMBOL_GPL(nvdimm_forget_poison);

#ifdef CONFIG_BLK_DEV_INTEGRITY
int nd_integrity_init(struct gendisk *disk, unsigned long meta_size)
{
	struct blk_integrity bi;

	if (meta_size == 0)
		return 0;

	memset(&bi, 0, sizeof(bi));

	bi.tuple_size = meta_size;
	bi.tag_size = meta_size;

	blk_integrity_register(disk, &bi);
	blk_queue_max_integrity_segments(disk->queue, 1);

	return 0;
}
EXPORT_SYMBOL(nd_integrity_init);

#else /* CONFIG_BLK_DEV_INTEGRITY */
int nd_integrity_init(struct gendisk *disk, unsigned long meta_size)
{
	return 0;
}
EXPORT_SYMBOL(nd_integrity_init);

#endif

static __init int libnvdimm_init(void)
{
	int rc;

	rc = nvdimm_bus_init();
	if (rc)
		return rc;
	rc = nvdimm_init();
	if (rc)
		goto err_dimm;
	rc = nd_region_init();
	if (rc)
		goto err_region;
	return 0;
 err_region:
	nvdimm_exit();
 err_dimm:
	nvdimm_bus_exit();
	return rc;
}

static __exit void libnvdimm_exit(void)
{
	WARN_ON(!list_empty(&nvdimm_bus_list));
	nd_region_exit();
	nvdimm_exit();
	nvdimm_bus_exit();
	nd_region_devs_exit();
	nvdimm_devs_exit();
}

MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Intel Corporation");
subsys_initcall(libnvdimm_init);
module_exit(libnvdimm_exit);